(toplevel) Small terminal screens do not fit and causes rendering error

Learning
1

Summary

To save your time, let’s jump to the conclusion:

OCaml’s default toplevel / interactive shell probably has some render issues. If you try:

4nji@Gra ~/d/o/pdf_copypaste> ocaml
OCaml version 5.0.0
Enter #help;; for help.

# Unix.sleep 1;;

You’ll get:

Alert ocaml_deprecated_auto_include:
OCaml's lib directory layout changed in 5.0. The unix subdirectory has been
# Unix.sleep 1;;ded to the search path, but you should add -I +unix to the
command-line to silence this alert (e.g. by adding unix to the list of
libraries in your dune file, or adding use_unix to your _tags file for
ocamlbuild, or using -package unix for ocamlfind).
Error: Reference to undefined global `Unix'
#

Notice that the 3rd line of Alert message was overwritten by my previous input, causing confusion.

You’ll need a window-sized terminal (with <= 65 columns) which has a rather small screen buffer to reproduce the bug.

(end of summary)

Hello! A very random topic / issue / question here. Could be a bug tho.

~/ocaml $ rlwrap ocaml
OCaml version 5.1.0+dev1-2022-06-09
Enter #help;; for help.

# Unix.sleep 1;;
Alert ocaml_deprecated_auto_include:
OCaml's lib directory layout changed in 5.0. The unix subdirectory has been
automatically added to the search path, but yo# Unix.sleep 1;;+unix to the
command-line to silence this alert (e.g. by adding unix to the list of
libraries in your dune file, or adding use_unix to your _tags file for
ocamlbuild, or using -package unix for ocamlfind).

Error: Reference to undefined global `Unix'
Hint: This means that the interface of a module is loaded, but its implementation is not.
      Found /data/data/com.termux/files/usr/lib/ocaml/unix/unix.cma
      in the load paths. Did you mean to load it using #load "unix.cma"
      or by passing it as an argument to the toplevel?
#

Then I Ctrl-D to terminate the process and changed the columns & rows of my terminal, then do the same thing again

~/ocaml $ rlwrap ocaml
OCaml version 5.1.0+dev1-2022-06-09
Enter #help;; for help.

# Unix.sleep 1;;
Alert ocaml_deprecated_auto_include:
OCaml's lib directory layout changed in 5.0. The unix subdirectory has been
# Unix.sleep 1;;ded to the search path, but you should add -I +unix to the
command-line to silence this alert (e.g. by adding unix to the list of
libraries in your dune file, or adding use_unix to your _tags file for
ocamlbuild, or using -package unix for ocamlfind).

Error: Reference to undefined global `Unix'
Hint: This means that the interface of a module is loaded, but its implementation is not.
      Found /data/data/com.termux/files/usr/lib/ocaml/unix/unix.cma
      in the load paths. Did you mean to load it using #load "unix.cma"
      or by passing it as an argument to the toplevel?

What am I missing here? Is this a random bug?

update

I tried this on my macOS with OCaml 5.0.0, I think it’s officially a bug now

4nji@Gra ~> rlwrap ocaml
OCaml version 5.0.0
Enter #help;; for help.

# Unix.sleep 1;;
Alert ocaml_deprecated_auto_include:
OCaml's lib directory layout changed in 5.0. The unix subdirectory has been
# Unix.sleep 1;;ded to the search path, but you should add -I +unix to the
command-line to silence this alert (e.g. by adding unix to the list of
libraries in your dune file, or adding use_unix to your _tags file for
ocamlbuild, or using -package unix for ocamlfind).
Error: Reference to undefined global `Unix'
#

Both Android (Termux) and macOS Big Sur have the same issue

2

截屏2023-03-21 19.03.09
截屏2023-03-21 19.03.091292×825 125 KB

3

I am not sure sure what bug you are trying to describe?

4

The console output was messed up

5

Ok, this indeed looks like some strange interaction between the REPL and the terminal line wrapping.

1 Like
6

Should I open an issue on github page?

7

Recording the issue might be a good idea.

8

So the bug goes like this: if you’re using a window-sized terminal which does not have enough screen buffer - like an Android smartphone, or a window-sized terminal on your PC, the error message would be overwritten by user’s input

4nji@Gra ~> rlwrap ocaml
OCaml version 5.0.0
Enter #help;; for help.

# Unix.sleep 1;;
Alert ocaml_deprecated_auto_include:
OCaml's lib directory layout changed in 5.0. The unix subdirectory has been
# Unix.sleep 1;;ded to the search path, but you should add -I +unix to the
command-line to silence this alert (e.g. by adding unix to the list of
libraries in your dune file, or adding use_unix to your _tags file for
ocamlbuild, or using -package unix for ocamlfind).
Error: Reference to undefined global `Unix'
#
4nji@Gra ~> python3 -c 'import os; print(os.get_terminal_size())'
os.terminal_size(columns=65, lines=17)
4nji@Gra ~>

I noticed that the error message output’s size (columns & rows) was hard-coded

Update

I changed the post’s title and opened an issue on github. I’m not sure if this is a rlwrap problem or OCaml default toplevel problem.

Update again

It’s a confirmed toplevel problem, cuz I tried without rlwrap.